South Africa’s President Jacob Zuma will face a challenge for the leadership of the ANC next week from his deputy, Kgalema Motlanthe.Mr Motlanthe’s  spokesman Thabo Masebe said that Mr Motlanthe had accepted his nomination to stand as ANC leader.Mr Zuma has received most nominations, but his critics say he has failed to tackle South Africa’s problems.The African National Congress leader will be overwhelming favourite to win elections due in 2014.Mr Masebe said Mr Motlanthe had agreed to run for the ANC leadership after being nominated by branches."He’s always said branches must be given a chance to express their free will,” Mr Masebe said.Mr Motlanthe was also available to continue serving as deputy president, he said.The ANC will hold leadership elections at its conference in Mangaung which starts on Sunday.Analysts say Mr Zuma is likely to be re-elected, having majority support in six of South Africa’s nine provinces.Mr Zuma was elected ANC leader at its last conference in 2007 following a bruising battle with then-President Thabo Mbeki.